1. Field of the Invention
The present invention relates to the manufacture of endodontic instruments, and more particularly, to the manufacture of such instruments by grinding a wire stock.
2. Description of the Prior Art
Endodontic instruments commonly referred to as files are utilized by dentists for cleaning and enlarging the root canals of human teeth. The purpose of the cleaning and enlarging procedure is to remove infected tissue from the root canals and enlarging the root canals so that they can be filled. A commonly used such endodontic instrument is known as a K-type file which has a tapered shaft including three or four spiral flutes along the length thereof. A preferred form of K-file includes three flutes, the cross-sectional shape of the shaft is triangular and the flutes form three spiral cutting edges along the length of the tapered portion of the shaft. Another type of endodontic instrument, known as a reamer, has three or four spiral flutes forming three or four spiral cutting edges thereon. These and other endodontic instruments are manufactured in accordance with standards set up by the American Dental Association and other standardizing bodies. For example, a standard K-type file ranges in tip size from 6 mm to 140 mm and in length from 21 mm to 31 mm. The total number of spirals varies depending on the size of the instrument and whether the instrument is a K-type file, a reamer or other type of file. The overall length of the spiraled portion of each instrument is a minimum of 16 millimeters and the diametric taper is 0.02 millimeter change in diameter per millimeter in length.
While various machining processes and apparatus for producing endodontic instruments have been developed and utilized, a particularly suitable process and apparatus are described in U.S. Pat. No. 4,999,952 dated Mar. 19, 1991 and U.S. Pat. No. 5,065,549 dated Nov. 19, 1991, both to Speiser et al., and both of which are incorporated herein and made a part hereof by reference thereto.
While the machining process and apparatus disclosed in the above mentioned patents to Speiser et al. have been used successfully for the manufacture of endodontic instruments of the types described above, there is a continuing need for improvements to such process and apparatus whereby the time and cost involved in machining each instrument are reduced.